In the past, mobile devices such as cell phones were limited to voice service and rudimentary data services. But mobile devices are quickly evolving into full fledged multi-media devices capable of voice service, e-mail service, text messaging, and even video-on-demand. New broadband network access services must be employed to provide the bandwidth and service quality required by these rapidly evolving services.
One such broadband network access service is referred to as “WiMAX”. WiMAX is defined as Worldwide Interoperability for Microwave Access by the WiMAX Forum, formed in June 2001 to promote conformance and interoperability of the IEEE 802.16 standard, officially known as WirelessMAN.
The WiMAX Forum NWG (network working group) has defined a multi-domain mobility architecture including many functional entities (FEs) to support full mobility and multi-domain roaming within a WiMAX network. But the WiMAX NWG has not yet defined a solution for implementing the communications between FEs that must occur to implement full mobility. One current proposal suggests defining relay, routing, and session management at the FE functional layer. This means IP routing infrastructure and protocols must be reinvented at the application layer, so this is not a practical solution. Another proposal suggests implementing IP multicasting in all nodes. But the gateway and base station portions of an access service node in a WiMAX network are peripheral devices that do not typically implement IP transport functionality such as IP multicast. In order to require such would lead to significantly increased cost for these devices.
What is needed is a communication protocol for carrying WiMAX control plane traffic, which preferably provides a low-cost, scalable, interoperable and standard-compliant solution.